Looking at downsizing and have pretty much narrowed it down to the Sunseeker 2500TS or the 2650S.

Any comments or concerns with these two units??

Also, currently driving a 2001 36ft Class A (diesel). I have seen numerous posts about the drivability of a Class C and that they often need additional add-ons to improve handling. I am leaning toward the Ford (as it irks me to give GM a single dollar of my money). What type of add-ons are we talking about??
Do they drive okay before and/or after??

The must have drivability mods for the ford imo are front end alignment to the specs in this forum just do a search here for them. A steering stabilizer and tires at correct air pressure. Do not know if you are talking new or used but i would also recommend rear air bags. as far as driving ok before and after yes it drove a lot better after the mods